From DE 103 57 741 A1, a variable valve device for an internal combustion engine and a method thereof are known. In the internal combustion engine which is equipped with the variable valve device, a target lift amount of an intake valve is limited to a predetermined value or greater if the variation in combustion reaches an allowable value or greater. The variable valve device changes the lift amount of the intake valve if the target lift amount of the intake valve is the predetermined value or less.